Add parsing for ambient declarations

test/mjsunit/harmony/typesystem/variable-declarations.js

Index: test/mjsunit/harmony/typesystem/variable-declarations.js
diff --git a/test/mjsunit/harmony/typesystem/variable-declarations.js b/test/mjsunit/harmony/typesystem/variable-declarations.js
index 50214804ed32ee2abde2f8bbcae17a78721ba609..f242255bb262e6dd2af4bcbf0b5a170f4d6e4744 100644
--- a/test/mjsunit/harmony/typesystem/variable-declarations.js
+++ b/test/mjsunit/harmony/typesystem/variable-declarations.js
@@ -51,13 +51,9 @@ function InvalidVariableDeclarations(size, keyword="var") {
       keyword != "const" && (t => keyword + " {a: x, b: y} : " + t + ";"),
       t => keyword + " {a: x, b: y} : " + t + " = {a: 17, b: 42};"
     ]),
-    "var [x, y]: number[];",
-    "var {a: x, b: y}: {a: number, b: string};",
-    "let [x, y]: number[];",
-    "let {a: x, b: y}: {a: number, b: string};",
-    "const x: number;",
-    "const [x, y]: [number, string];",
-    "const {a: x, b: y}: {a: number, b: string};"
+    keyword + " [x, y]: number[];",
+    keyword + " {a: x, b: y}: {a: number, b: string};",
+    keyword == "const" && keyword + " x: number;"
   ]);
 }